*The dispersion agent(hereout referred to as CAB), lamponite clay and PVA formed a sort of suspension in the water/organic solvent solution. It did not appear to fully dissolve. Used a spatula to scrape the side of the RB flask in order to try and break up the large chunks.

*The dispersion agent(hereout referred to as CAB), lamponite clay and PVA formed a sort of suspension in the water/organic solvent solution. It did not appear to fully dissolve. Used a spatula to scrape the side of the RB flask in order to try and break up the large chunks.

−

*

+

* After addition to heat, the large chunks generally broke apart. Small spheres seemed to be forming after approximately an hour spinning.

PVA Microspheres

Reaction should be carried out using a reflux condenser and a thermostatic water bath of 55°C.

Dissolve 1g total of PVA and clay additive in 5mL hot,deionized water.

Acidify the solution using 0.25mL 0.5M H2SO4.

Dissolve 0.6g Cellulose acetate butyrate in 25mL 1,2-dichloroethane.

Pour the acidified PVA solution into the 25mL 1,2-dichloroethane solution.

Stir the water/1,2-dichlorethane solution for 30 minutes.

After 30 minutes stirring, add 0.75mL glutaraldehyde to the solution.

After the addition of glutaraldehyde, allow the reaction to carry out for 3 additional hours at 55°C.

Filter the produced microspheres from the solution using a a sintered glass filter and a vacuum.

Wash the collected microspheres using the following solvents in the following order:

1,2-dichloroethane

acetone

hot water

cold water

methanol

Dry the microspheres at 60°C overnight.

The following procedure was adapted from the article Poly(vinyl alcohol) microspheres with pH- and thermosensitive properties as temperature-controlled drug delivery [1]

1,2-dichlorethane safety:

1,2-dichloroethane is highly flammable. Care must be used at all times when dealing with 1,2-dichloroethane

Avoid all 1,2-dichloroethane skin contact by wearing gloves and googles.

Avoid any 1,2-dichlorethane contact with extreme heat, open flame, or electrical sparks.

1,2-dichloroethane should be kept in the flammable storage safety cabinet when not in use.

When in use, 1,2-dichloroethane should be kept in the fume hood.

PVA Microsphere information:

Preparation of Microspheres using PVA MW 146,000-186,000

'

Amount of PVA added(g)

0.9004

Amount of Lamponite clay added(g)

0.1003

Amount of cellulose acetate butyrate added(g)

0.6066

Amount of GA added(mL)

Amount of H2SO4 added(mL)

0.25

Observations:

The dispersion agent(hereout referred to as CAB), lamponite clay and PVA formed a sort of suspension in the water/organic solvent solution. It did not appear to fully dissolve. Used a spatula to scrape the side of the RB flask in order to try and break up the large chunks.

After addition to heat, the large chunks generally broke apart. Small spheres seemed to be forming after approximately an hour spinning.